LSM: Separate idea of "major" LSM from "exclusive" LSM

In order to both support old "security=" Legacy Major LSM selection, and
handling real exclusivity, this creates LSM_FLAG_EXCLUSIVE and updates
the selection logic to handle them.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
This commit is contained in:
Kees Cook 2018-09-19 19:57:06 -07:00
parent 7e611486d9
commit 14bd99c821
6 changed files with 17 additions and 4 deletions

View File

@ -2043,6 +2043,7 @@ extern void security_add_hooks(struct security_hook_list *hooks, int count,
char *lsm);
#define LSM_FLAG_LEGACY_MAJOR BIT(0)
#define LSM_FLAG_EXCLUSIVE BIT(1)
struct lsm_info {
const char *name; /* Required. */

View File

@ -1723,7 +1723,7 @@ alloc_out:
DEFINE_LSM(apparmor) = {
.name = "apparmor",
.flags = LSM_FLAG_LEGACY_MAJOR,
.flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE,
.enabled = &apparmor_enabled,
.init = apparmor_init,
};

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@ -49,6 +49,7 @@ static __initconst const char * const builtin_lsm_order = CONFIG_LSM;
/* Ordered list of LSMs to initialize. */
static __initdata struct lsm_info **ordered_lsms;
static __initdata struct lsm_info *exclusive;
static __initdata bool debug;
#define init_debug(...) \
@ -129,6 +130,12 @@ static bool __init lsm_allowed(struct lsm_info *lsm)
if (!is_enabled(lsm))
return false;
/* Not allowed if another exclusive LSM already initialized. */
if ((lsm->flags & LSM_FLAG_EXCLUSIVE) && exclusive) {
init_debug("exclusive disabled: %s\n", lsm->name);
return false;
}
return true;
}
@ -144,6 +151,11 @@ static void __init maybe_initialize_lsm(struct lsm_info *lsm)
if (enabled) {
int ret;
if ((lsm->flags & LSM_FLAG_EXCLUSIVE) && !exclusive) {
exclusive = lsm;
init_debug("exclusive chosen: %s\n", lsm->name);
}
init_debug("initializing %s\n", lsm->name);
ret = lsm->init();
WARN(ret, "%s failed to initialize: %d\n", lsm->name, ret);

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@ -6989,7 +6989,7 @@ void selinux_complete_init(void)
all processes and objects when they are created. */
DEFINE_LSM(selinux) = {
.name = "selinux",
.flags = LSM_FLAG_LEGACY_MAJOR,
.flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE,
.enabled = &selinux_enabled,
.init = selinux_init,
};

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@ -4809,6 +4809,6 @@ static __init int smack_init(void)
*/
DEFINE_LSM(smack) = {
.name = "smack",
.flags = LSM_FLAG_LEGACY_MAJOR,
.flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE,
.init = smack_init,
};

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@ -550,6 +550,6 @@ static int __init tomoyo_init(void)
DEFINE_LSM(tomoyo) = {
.name = "tomoyo",
.flags = LSM_FLAG_LEGACY_MAJOR,
.flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE,
.init = tomoyo_init,
};